Spacecraft/Satellite thrusters, proplusion systems and retro thrusters etc.

[Indx TechStyle]

Turns out ISRO has also flown 1 W Radioisotope heater unit(RHU) tech demo on propulsion module
RHU is used to keep spacecraft warm during cold nights. They are preparing for long duration lunar missions in future Image for reference only #Chandrayaan3

https://twitter.com/hashtag/Chandrayaan3?src=hashtag_click

Some more confirmation of RHU unit. I am sooo happy right nowl Flight demo in immediate missions and turns out it was Chandrayaan 3

 

[Swesh]

BARC paper in RHU

 

[Indx TechStyle]

Electric propulsion systems

 

[Indx TechStyle]

About TDS-01 electric thrusters from Reddit (1 year old post from Ohsin).
Upcoming Technology Demonstration Satellite 01 (TDS-01) will be on PSLV-C54. Launch aiming for end of March 2022.

Two official communiqué from Institute of Plasma Research, Gandhinagar and CSIR-CEERI, Pilani suggest PSLV-C54 would carry Technology Demonstration Satellite 01 (TDS-01) which is supposed to host demonstrators for Electric Propulsion system, indigenous atomic clock and Travelling Wave Tube Amplifier (TWTA).
Following is an excerpt from newsletter of Institute of Plasma Research, Gandhinagar (Issue 103, Feb 2022) about 'hand over' event held on 27 Dec 2021 for delivering BN/SiO2 ceramic material developed for VSSC-ISRO to be used on 300 mN EPS thrusters.
[PDF] [Archived]


Second source is this press release from CSIR-CEERI, Pilani about virtual 'hand over' event held on 27 Dec 2021 for Thermionic Emitters cathode they developed for VSSC-ISRO to be used on electric propulsion thrusters.
[PDF] (Hindi) [Archived]
This translated report from Dainik Bhaskar summarises it. Press release again mentions PSLV-C54 and EPS but refers to spacecraft as "STS-1" which might be a typo and probably they meant TDS-01. Not yet sure if PSLV-C54 / TDS-1 would be GSO bound or not. Launch is close, it was supposed to be in Q4 2021 but per SANA registry now tentatively on 29 March 2022.
Those 300mN thrusters have been developed for a while and used to often get mentioned in various presentations like here and here. While we know GSAT-9 had 18mN thrusters (by Keldysh Research Centre), they were meant for North South Station Keeping (NSSK) operation and not for orbit raising manoeuvres which were done by conventional chemical propulsion (LAM engine). These new 300mN thruster will perhaps be used for orbit raising in future GSO bound 'all EPS' spacecrafts.

Update on TDS-01.
ISRO to demonstrate indigenously developed electric propulsion system on satellite
The system will be demonstrated on board a Technology Demonstration Satellite that is expected to be launched in the second half of 2024.

The Indian Space Research Organisation (ISRO) is gearing up to demonstrate the use of an indigenously built electric propulsion system on a satellite later this year.

The system, featuring a 300 millinewton (mN) thruster, will be demonstrated on board a Technology Demonstration Satellite (TDS-01) that is expected to be launched in the second half of 2024, V. Narayanan, Director of Liquid Propulsion Systems Centre (LPSC), the lead ISRO centre working on the technology, told The Hindu.

Chemical propellants now

Functions such as orbital raising and station-keeping once the satellite is in orbit will be performed using electric propulsion, Manju S. Nair, Project Director, LPSC, said. At present, ISRO satellites employ chemical propellants for such operations.

The space agency has been working on electric propulsion so as to cut down dependence on chemical propellants. What makes the upcoming mission special is that the propulsion system has been fully developed in India. In 2017, ISRO demonstrated an electric propulsion system equipped with an 18 mN thruster aboard the GSAT-9 satellite. But in that instance, the thruster was imported while the power processing units were developed in-house by ISRO.

The new system promises 300 mN thrust and a specific impulse of around 2000 seconds with 5kW electric power supply, Dr. Nair said. The thruster works by generation of plasma, thereby generating the required thrust. The LPSC has so far completed approximately 500 hours of tests on the system and the final tests are under way.

A comparison

Compared to chemical propellants, electric propulsion is more efficient and gives you a lighter satellite for the same payload capacity. The specific impulse is five to six times higher than that of chemical propulsion.

“Which means, we can bring down the satellite mass. For example, for a 5,000-kg communication satellite which has a 900-1,000 kg ‘useful payload,’ we can bring down the total mass of the satellite to about 3,500 kg,” Dr. Narayanan said.

The 300mN thruster used for this electric propulsion system was on display at the Vikram Sarabhai Space Centre (VSSC) on Wednesday in connection with the ‘SemiconIndia 2024: Future Design’ summit. TDS-01 is scheduled to be launched aboard a Polar Satellite Launch Vehicle (PSLV) mission.